Lighting Device Using Short Thermal Path Cooling Technology and other Device Cooling By Placing Selected Openings on Heat Sinks

ABSTRACT

A novel heat sinking technology, uniquely adaptive to LED lighting devices in a generally LED array format containing multiple openings on said heat sink&#39;s base portions and optionally fin portions providing “short path cooling” technology. The “short path cooling” technology is thoroughly taught with multiple examples. Also taught, are methods of heat sink area maintenance when said openings are placed on said heat sinks. Indeed, even surface area increases are shown to be possible when multiple openings are placed on said heat sinks. Lastly, other non-LED semiconductor cooling is discussed and illustrated in various figures using said “short path cooling” technology.

CLAIM OF PRIORITY

This patent application is a continuation and claims priority from U.S.utility patent application Ser. No. 14/998,489, entitled ‘Lightingdevice using short thermal path cooling technology and other devicecooling by placing selected openings on heat sinks’, filed on Jan. 12,2016.

BACKGROUND—FIELD OF THE INVENTION

In a class of embodiments, the present invention is a heat sinkingtechnology applied, but not limited to, electrical lighting devices,namely devices using Light Emitting Diodes (LEDs) in an assembly with aheat sink technology that is more efficient than current designs andthus helps keep the LEDs cooler.

In this present 21^(st) century, with the advent of the high brightnessLight Emitting Diode (LED), these said LEDs have begun to replace theelectrically less efficient incandescent light bulbs and fluorescenttubes. Presently, there is no such device as a “white light” emittingsemiconductor diode. Light emitting diode chips emit an almostmonochromatic light of predominantly one wavelength or a few closelyspaced wavelengths. White LEDs use blue or ultra violet light emittingsilicon chips. This blue or ultra violet light excites a phosphor whichin turn emits white light by a process known as the Stokes shiftemission. Using an appropriate mix of phosphor types, a white light canbe produced. For example a white LED can be made that is “a warm light”or “a cool light”. This is the same as in fluorescent tubetechnology—obviously so—they both use phosphors for white lightemission.

Before the invention of the light emitting diode (emitting infra-redlight) manifested publicly in the form of U.S. Pat. No. 3,293,513, and ablue LED, U.S. Pat. No. 3,819,974, and eventually a white LED, U.S. Pat.No. 5,998,925, electrical lighting was based upon high temperaturephenomena. Take for example, a white-hot tungsten filament in thefamiliar domestic incandescent light bulb. Later the fluorescent tubewas developed which used high temperature ionized gas technology to emitultra violet light, which in turn exited a phosphor inside the saidtube, producing white light. This is well and good. However there is amajor problem . . . .

Past light emitting devices (excepting chemical or bio-luminescent) fromthe candle to the incandescent filament bulb to the electric gaseousdischarge tube etc. required a high temperature for the lightproduction.

This means that the said light producing devices of the past could nottolerate a low temperature environment. Hence they were enclosed in aninsulated enclosure, generally made of a borosilicate glass or quartzmaterial; the candle or oil lamp being an obvious exception since theyuse a fuel other than electricity and consume oxygen. Indeed the famousNobel Prize Laureate Irving Langmuir improved upon the Edisonincandescent light bulb by placing a gas into the formally vacuumenvironment of Edison's incandescent light bulb (U.S. Pat. No.1,180,159). The inert gas in Langmuir's light bulb produced aninsulative effect, (see page 2 lines 30-41 and 71-74 of said patent) byreducing the heat dissipation of the said filament, thus requiring lesselectrical energy to be supplied to the said filament.

What does this mean and of what relevancy is this to the presentteaching? Very much indeed. Virtually all light fixtures in the worldfrom the elegant chandelier in the kings palace to the naked light bulbdeep in the underground mine do not overly concern themselves withcooling the light fixture. In very high power light fixtures likeHollywood film studios for example, they indeed do cool these lights;but only to prevent these powerful light bulbs from self-destruction dueto their very high power per unit volume design.

Now in the United States and in some other countries, two forces havecome into play:

a. The power of technology, with the invention of the LED and

b. The power of government, with legislated mandates.

The former power has given us high brightness LEDs and the latter poweris banning mercury, a necessary ingredient in efficient fluorescenttubes. Also electrical energy-saving mandates are being imposed. Thereare literally billions of conventional light fixtures in the UnitedStates, let alone the rest of the world. And almost without exception,they all dissipate heat poorly.

The LED is not a high temperature light emitting device. It requirescooling.

Indeed if one inspects the typical LED device datasheet, he or she willdiscover that in some cases the light output and electricalspecification is measured at 25° C., i.e. room temperature. (Good luckengineers, at achieving this capability while lighting up these LEDs).Basic physics teaches us that for heat transfer to occur we must have adelta T (ΔT)—a temperature difference for heat to flow from hotter tocooler. Therefore the typical LED, when operating, will always be about20 to 30° C. hotter than the heat sink. And then, the heat sink mustalso be hotter than the ambient air.

In the business, cool LEDs live a long time, while hot LEDs die young.

Also, the greater the ΔT, the smaller is the area required for aheatsink to dissipate a given BTU (British thermal unit) of heat. Nowtherefore, common incandescent light bulbs operate at ≈2500° C., whileLEDs should operate at a silicon junction temperature of <100° C. forlong life. This explains why LED chips require huge heat sinks relativeto their size.

Due to the afore mentioned government mandates, an ongoing industry hassprung up solely for the purpose of retro-fitting the incandescent andgaseous tube fixtures with LED based light bulbs, tubes, arrays etc. Atruly proverbial square peg forced into a round hole, since all theseconventional fixtures provide a hostile environment to the cooling arts.This is not the case with new building designs. The architect has aplethora of wonderful LED light fixtures, properly designed by competentengineering companies. But for each new building there are perhapsthousands of older buildings let alone street lights etc. that need tobe accommodated with these new LED devices.

Definition of Terms

For the purposes of the present disclosure, the Abstract portion of thisdocument is to enable the public, and especially the scientists,engineers, and practitioners in the art who are not familiar with patentor legal terms or phraseology, to determine quickly from a cursoryinspection, the nature and essence of the technical disclosure of theapplication. The Abstract is neither intended to define the inventiveconcept(s) of the application, which is measured by the claims, nor isit intended to be limiting as to the scope of the inventive concept(s)in any way.

For the purposes of the present disclosure, the phrase “A and/or B”means (A), (B), or (A and B).

For the purposes of the present disclosure, the phrase “A, B, and/or C”means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).

The descriptions may use perspective-based descriptions such astop/bottom, in/out, over/under and the like. Such descriptions aremerely used to facilitate the discussion and are not intended torestrict the application of embodiments described herein to a particularorientation.

Thru out this teaching, the term “distal” is in reference with theobject; distal being further away, while proximal would be closer to theobject.

The description may use the phrases “in an embodiment,” or “inembodiments,” which may each refer to one or more of the same ordifferent embodiments. Furthermore, the terms “comprising”, “including”,“having”, and the like as used with respect to embodiments of thepresent disclosure, are synonymous.

The term “coupled with”, along with its derivatives, may be used herein.“Coupled” may mean one or more of the following. “Coupled” may mean thattwo or more elements are in direct physical or electrical contact.However, “coupled” may also mean that two or more elements indirectlycontact each other, but yet still cooperate or interact with each other,and may mean that one or more other elements are coupled or connectedbetween the elements that are said to be coupled with each other. Theterm “directly coupled” may mean that two or more elements are in directcontact.

Unless otherwise specified, throughout this disclosure, including in theclaims, the expressions “LED” denotes a light emitting diode or othersolid state device generally emitting a white light. It can also referto a red, green, blue, orange or yellow light emitting diode. It canalso refer to an RGB multi-chip diode assembly (RGB denotes ared/green/blue diode assembly in one package or three individual saiddiodes close together, capable of emitting each of its colors separatelyor all three together, simulating white light at a distance).

Unless otherwise specified, throughout this disclosure, including in theclaims, the expressions “OLED” (Organic Light Emitting Diode) denotes alight emitting device creating light with organic based technologyrather than silicon semiconductor based technology. It is presently usedin some cell phones. It can also refer to a red, green, blue or yellowOLED. It can also refer to an RGB OLED device. (RGB denotes ared/green/blue OLED device).

The term “tube” refers to a fluorescent tube or other gaseous lightsource; for example a low pressure sodium lamp etc.

The term “plug” or “base plug” generally refers to a lighting devicesbottom end piece having an electrical connector for plugging onto anelectrical socket. A similar example would be the common light bulb withthe base having a plug that engages to an electrical light socket.

The term “top” or “bottom” of a LED lighting device generally refers tothe opposite end of the said lighting device's base plug. A similarexample would be the common light bulb with the base being the bottomand the bulb being the top.

In this teaching, the expression “hoop device” is generally a supportdevice for long LED lighting devices such as depicted in FIGS. 1-13.These devices are generally necessary when used in horizontal or angularlight fixtures as a second support. These said hoop devices can be ahalf hoop device with two end-clip hooks or can also be full hoops withthe clip hooks placed internally at 180° apart.

In this teaching, the expression “PCB” denotes a printed circuit boardgenerally bonded to a thin metal cladding. The printed circuit boarditself is extremely thin, in the order of 0.005 inches or so and is avery poor conductor of heat, about 0.25 W/mK, (where W is watts ofpower, m is in square meters thru which the heat is conducting and K isthe temperature difference in degrees Kelvin) hence the extreme thinnessused. The said thin PCB is chemically bonded to an aluminum substrate, agood conductor with a thermal conductivity of about 140-201 W/mK(depending on alloy) or in high power applications, copper, whosethermal conductivity is about 430 W/mK whose thickness is substantiallygreater. The said metal substrate thickness can be as thin as 0.02inches to 0.25 inches or more.

Furthermore, the expression “PCB” can also denote a printed circuit on anonmetallic substrate such as ceramic which is available in a number ofvarieties and thermal conductivities. For example the military andaerospace industry has used beryllium oxide (BeO) ceramic material foryears. It has a high thermal conductivity, but is poisonous and veryexpensive.

Unless otherwise specified, “PCB of hybrid composition” is a PCBconsisting of copper traces electrically insulated from a base materialsuch as copper, aluminum, various ceramic powders or other highlythermally conductive materials. It is termed a hybrid printed circuitboard because it is constructed of a mixture of different materials.

Unless otherwise specified, the terms “heat sink” or “heat sinks”throughout this teaching refer to a relatively large surface area devicethat transfers conducted heat from a relatively very small area LED orother semiconductor heat source attached to the said heat sink devicewhich then dissipates the said heat to the ambient air thru the processof convection and radiation. These said heat sinks are generally made ofa selected metal or metal alloy, but are not limited to these.Plastic/composite and selected allotropes of carbon known as graphenehaving an anisotropic thermal characteristic are also possible. Tosummarize, the said heat sinks accept conducted heat and then dissipatethe said heat to the ambient atmosphere by convection and radiation.

The term “hole” or “holes” or “opening” as used on a heat sink or PC isdefined as a generally but not limited to an essentially circularopening thru a material usually but not limited to metal. It may bedrilled, milled, punched, pierced, cut with a laser etched or moldedetc. It does not necessarily need to be perfectly round, but can besquare, hexagonal or other shape/s. For example, laser cutting orchemical etching may produce various shape/s of polygon, star, crossetc.

The term “slot” or “slots” as used on a heat sink is defined as agenerally but not limited to a perimetrical, essentiallyoblong/rectangular opening thru a material usually but not limited tometal. It may be punched, milled, cut with a laser etched or molded etc.It does not necessarily need to be a perfect rectangle but can haveround ends such as an end mill would make, or can be square ended suchas a metal punch would produce. For example, laser cutting or chemicaletching can produce a variety of shapes of slots such as straight,curved, arced etc. Additionally, the said slots do not need to be fullslots in the sense that the said slots consists of two long sided andcorrespondingly two short sides; the said slots can have two long sidesand only one short side. For example, a slot can be cut into a heatsinkfin and continue to be cut until it cuts thru the fins top (top beingthe distal point from the base of the heat sink where the fin isattached) thus producing an open ended slot.

Unless otherwise directly or indirectly or by context defined, theexpression “L bend” refers to a generally 90° bend in a thin fin used onheat sinks. (The term 90° means exactly that—within the accuracy limitsof standard industry practice. The intent of this teaching and in theclaims is that 90° is in fact a variable, dependent on the accuracy ofthe industry practice.) The said “L bend” can also be greater or lessthan 90°, depending on design requirements. The “L” bent section widthand angle is selected by the designer.

Unless otherwise directly or indirectly or by context defined, theexpression “first side” and “second side” of a heat sink's base portionor fin portion refers to a heatsinks base or fin large area sections andnot to their edge portions.

Unless otherwise directly or indirectly or by context defined, theexpression “cooling medium” is generally ambient air, but can be othergas/gasses or liquids. The said cooling medium can be forced flow ornon-forced flow.

The term “maintains surface area” or “surface area maintaining” as usedin this teaching and/or the claims means the removal of heat sinkmaterial to produce selected holes, slots or other shape openings suchthat the total heat sink area exposed to air or other cooling gasses orliquids is not substantially reduced. For example, the reduction in saidheat sink surface area can be allowed to be as high as 30% to 50% ormore if it produces a more efficient heat sink due to better air orother gas or liquid flow thru said heat sink. But generally it is anideal goal to either maintain the same said surface area of said heatsink or to even increase the said area by a technique taught in thisdisclosure.

A deliberate reduction in said surface area may be desired to allow acooling medium to flow thru more freely to cool other items as desired.For example, an electrical apparatus in a cabinet may have a pluralityof individual heat sinks which need cooling air coming from a first sideof said cabinet and this said cooling air has to be directed to variousheat sinks in said cabinet and then exit out thru a second side of saidcabinet. Therefore, heatsinks near the fresh air entry may need to be oflesser area per unit watt/BTU dissipation, while heatsinks far from thesaid fresh air entry may need to be of larger area per unit watt/BTUdissipation,

The term “matching” or “PCB matching” or “heat sink matching” inreference to holes or slots being placed on a selected area of a PCB ora heat sink generally denotes a matched set of holes or slots on thesaid pair of items (namely a PCB mated to a heat sink). The saidmatching does not necessarily have to be perfect. For example, a hole orslot on a heat sink can be larger or smaller in dimension than on itsmating PCB and vice versa.

Unless otherwise specified, the term “air”, “air flow”, “air cooling”etc. generally refers to the ambient atmospheric air but is not limitedto the said ambient atmospheric air. In special cases such as forexample, the section of this teaching, “OTHER APPLICATIONS OF THEPRESENT INVENTION”, it can refer to other gasses or liquids.

The vernacular term “breathe” as used in this disclosure refers to aheat sink or an entire LED lighting device being designed in such amanner that allows free air to circulate in and around the said heatsink/LED lighting device as freely as possible, providing efficientcooling.

The terms “edge effect”, “boundary layer”, “Bernoulli principle”,“Langmuir's laminar flow theory” and “crowding effect” etc. arethermodynamic terms whose definitions are available in a variety oftechnical text books or other publications on the said subject.Therefore these terms will not necessarily be defined in thisdisclosure.

The expression “mounted” generally applies to a fixture affixed in itsplace using industry professional procedures such as bolting, screwing,nailing, gluing, clinching, interference press fitting, clamping etc.

The term “ballast” can refer to an inductive electrical current limitingdevice or an electronic device that may perform both current limitingand power supply functions. In special cases, other electronic controlfunctions may be incorporated. For example, wired or wireless controlfor various functions such as for example, Pulse Width Modulation, PulseFrequency Modulation, Spread Spectrum Pulse Modulation of LEDs etc.Other functions can be included, such as ambient light sensors,occupancy sensors, timers, wireless transmission and reception forcontrol and status reporting etc.

Thru out this teaching, electrical wire connections will not be shown.They are well known to the technical art.

Unless otherwise specified, thru out this teaching, light fixturebezels, dust covers, decorative trim etc. will not be shown. They arealso well known in the art.

BRIEF DESCRIPTION OF THE PRIOR ART

Several devices related to the present invention have been identifiedduring this inventor's Due Diligence Search. They are as follows:

Patent Application US 2011/0115358 by Kim discloses a LED light bulbusing side emitting LED devices.

Kim discusses a plurality of heatsinks each for a group of LEDs. Thepresent invention discuses a plurality of heatsinks, but with speciallydesigned holes or slots for better air flow. Kim also discusses aplurality of light diffusers. The present invention discuses only onelight diffuser/light cover/dust cover which is made with openings toallow air flow.

KIM discusses a central hollow pillar for mounting LED module units in astacked format. The present invention discuses a central pillar or hub,but teaches a radial placement of a plurality of LED modules in a radialfashion.

Patent Application US 2012/0075859 by Granado et al. discloses a LEDlighting device using high power LED assemblies.

Granado uses a large finned heat sink for cooling the LEDs. Granadoteaches a large base portion with a power connector and complex powerconversion circuitry in the said base portion. The present inventiondiscuses a single heat sink or a plurality of heatsinks, but withspecially designed holes or slots for better air flow. Granado does notteach this. The present invention also teaches a base portion with apower connector but not with the complexity of Granado. Indeed, thepresent invention initially offers the first embodiment using a baseportion with no built-in power circuits and low power LEDs and otherembodiments with simple electronic ballasts.

Patent U.S. Pat. No. 8,952,613 to Anderson et al. teaches cooling airentering thru a transparent cover portion to cool the covered heatsinkarea of an incandescent light bulb LED replacement device. This is anexcellent start for more cooling efficiency. The present inventiondiscuses a heat sink and a plurality of heatsinks for a substantiallylarger fixture containing fifty (50) to over two hundred (200)individual LEDs, but with specially designed holes or slots for betterair flow. Anderson does not teach this. The present invention alsodiscusses an optional light diffuser/light cover/dust cover which ismade with dozens of relatively small openings closely spaced to allow arelatively large air flow to a much larger light fixture than the lightbulb type Anderson speaks of.

Patent U.S. Pat. No. 8,944,669 to Chien discloses a LED lighting deviceusing removable LED assemblies in a track format, which said tracks canbe arranged in a plethora of differing configurations. A wonderfulpatent, clearly, thoroughly thought out. However, Chien does not teachshort path heatsink cooling as does the present invention.

Patent U.S. Pat. No. 9,068,738 to Auyeung discloses a LED lightingdevice with a heatsink having holes in the fins. This is awell-engineered design with excellent optics for even lightdistribution.

The present invention discuses a plurality of heatsinks, but withspecially designed holes or slots for better air flow. Additionally, thepresent invention teaches that holes or other openings in heat sink finsshould be of a size to maintain exposed said fin surface area. Auyeungdoes not; neither does he teach openings in the base plate portion toallow short path air cooling to occur as does the present invention.

Patent U.S. Pat. No. 6,827,130 to Larson discloses a heat sink assemblywith holes in a closed “plenum” type of arrangement with forced aircooling.

The present invention discuses a plurality of heatsinks, but withspecially designed holes or slots for better air flow. Additionally, thepresent invention teaches that holes or other openings in heat sink finsshould be of a size to maintain exposed said fin surface area. Larsondoes not teach this; neither does he emphasize non-forced ambient aircooling for his heat sink device.

Patent U.S. Pat. No. 9,091,424 to Mart et al. discloses a “LED LightBulb”; a misnomer of sorts, but nevertheless a LED lighting device thatcan be used as a track light etc. Mart discusses holes (he calls themvents) in the front face of the lighting device that is an integralhousing and heatsink assembly. The said holes extend thru the body ofthe said LED lighting device from front to back. A fan is placed in therear and air is forced thru the said LED lighting device body to coolthe said body. Mart teaches that for lower power LED lighting devices afan is not necessary.

The present invention discuses a plurality of heatsinks, but withspecially designed holes or slots for better air flow preferably withoutusing a fan in lighting applications due to fan noise and fanreliability. Additionally, the present invention teaches that holes orother openings in heat sink fins should be of a size to maintain exposedsaid fin surface area. Mart does not teach this; neither does heemphasize hole sizing or holes/slots on heatsink fins.

Mart does state in column 4, lines 32-35: “ . . . . In at least someembodiments, the number of vents is dependent on the amount of air flowneeded thru the interior of LED bulb100 to maintain the temperaturebelow the predetermined threshold”. Clearly, Mart understands basicthermal engineering principles. But he does not teach the maintaining ofheat sink fin surface area. Nor does he teach the cutting of openings toexpose selected heat sink fin base attachment areas as taught by thisinvention.

Patent U.S. Pat. No. 9,039,223 to Rudd et al. discloses a LED LightingFixture for high power applications such as streetlights. Rudd disclosesindividual LED arrays wherein each said LED array section is mounted ona separate heat sink and then these LED array/heat sink assemblies arejoined side by side into a plurality of assemblies to form the desiredlighting fixture.

The present invention mounts a plurality of LEDs on a heatsink fin, andthen attaches them not side by side, but one heat sink fin in front ofanother to complete a desired lighting fixture. Furthermore, slots,holes or other shaped openings are provided in the present invention toincrease the heat sinking efficiency using short path airflow techniquesRudd does not teach this. When using a conventional extruded aluminumheat sink, this invention also discloses various slots or other shapedopenings to allow short path air flow which results in the said heatsink becoming a more efficient heat dissipating unit. Rudd does notteach this.

BRIEF DESCRIPTION OF THE DRAWINGS

In a class of embodiments, the present invention consists of a BasePlugged Light Emitting Diode lighting device (one class of embodiments)coupled to an efficient heat sink (another class of embodiments). Alsothe same efficient heat sink technology is disclosed for other coolingfunctions. (yet another class of embodiments). The inventor understandsthat this disclosure could be a teaching solely for a more efficientheat sink, However it will become obvious that this new heat sinktechnology is uniquely applicable to the cooling of LED devices due tothe heat sink using carefully designed openings for efficient coolingand in selected embodiments using transverse slot openings on extrudedheat sinks or holes or other shaped openings etc. for non-extruded heatsinks for efficient air flow. The inventor claims by reference otherheat sink applications such as, for example efficient cooling of non LEDsemiconductor devices or liquid pipe cooling in high power electronicdevices etc. The inventor further understands that most configurationsof heat sinks do function if huge quantities of forced air flow areimpinged upon the said heat sinks. However, in the practical world ofdomestic, office, laboratory, studio, etc. lighting, forced air coolingis seldom used. This invention is ideal for generally ambient still aircooling.

The object and features of the present invention, as well as variousother features and advantages of the present invention will becomeapparent when examining the descriptions of various selected embodimentstaken in conjunction with the accompanying drawings and term definitionsin this document in which:

FIG. 1 shows a partially exploded perspective view of a First EmbodimentLED lighting device.

FIG. 2 shows an assembled perspective view of a LED lighting device in avertical position.

FIG. 3 shows an assembled perspective view of a LED lighting device in ahorizontal position.

FIG. 3A shows an assembled perspective view of a LED lighting device ina vertical position.

FIG. 3B shows a magnified view of a portion of FIG. 3A

FIG. 3C shows an assembled perspective view of a LED lighting device ina horizontal position.

FIG. 4 shows a partially exploded perspective view of a SecondEmbodiment LED lighting device.

FIG. 4A shows an example PCB layout of a Second Embodiment LED lightingdevice.

FIG. 5 shows an assembled perspective view of a Second Embodiment LEDlighting device.

FIG. 6 shows a perspective sectional view of a Second Embodiment LEDlighting device heat sink.

FIG. 7 shows a second perspective sectional view of a Second EmbodimentLED lighting device heat sink.

FIG. 8 shows an end view of a First Embodiment LED lighting device heatsink.

FIG. 9 shows an end view of a Second Embodiment LED lighting device heatsink.

FIG. 10 shows an assembled perspective view of a Third Embodiment LEDlighting device.

FIG. 11 shows a partial assembled perspective view of a Third EmbodimentLED lighting device.

FIG. 12 shows an assembled perspective view of a Fourth Embodiment LEDlighting device.

FIG. 13 shows a partial assembled perspective view of a FourthEmbodiment LED lighting device.

FIG. 14 shows a one-section perspective view of a Fifth Embodiment LEDlighting device.

FIG. 15 shows a one-section perspective view of a Sixth Embodiment LEDlighting device.

FIG. 15A shows a one-section perspective view of a Seventh EmbodimentLED lighting device.

FIG. 15B shows a one-section perspective view of a Eighth Embodiment LEDlighting device.

FIG. 16 shows a partially exploded perspective view of a NinthEmbodiment LED lighting device.

FIG. 17 shows an assembled perspective view of a Ninth Embodiment LEDlighting device.

FIG. 18 shows an assembled perspective view of a Tenth Embodiment LEDlighting device.

FIG. 18A shows a transparent or translucent protective plastic cover andbase as can be optionally used in said Tenth Embodiment LED lightingdevice.

FIG. 19 illustrates a perspective view of a first horizontallypositioned very common heat sink.

FIG. 20 illustrates a perspective view of a Eleventh Embodiment secondhorizontally positioned heat sink of the present invention.

FIG. 21 illustrates a sectional perspective view of a secondhorizontally positioned heat sink of the present invention.

FIG. 22 illustrates a perspective view of a Twelfth Embodiment thirdhorizontally positioned heat sink of the present invention.

FIG. 23 illustrates a perspective view of a Thirteenth Embodimenthorizontally positioned heat sink with power LEDs of the presentinvention.

FIG. 24 illustrates a perspective view of a Fourteenth Embodiment fourthhorizontally positioned heat sink of the present invention with sectionE-E indicated.

FIG. 25 illustrates a perspective view of a Fourteenth Embodimenthorizontally positioned heat sink of the present invention with sectionE-E shown in FIG. 24 removed and arrows F-F indicating further viewmagnification in FIG. 25A.

FIG. 25A illustrates a magnified sectional view F-F of FIG. 25.

FIG. 26 illustrates a perspective view of a Fifteenth Embodimenthorizontally positioned heat sink of the present invention showingarrows G-G.

FIG. 27 illustrates a perspective view of a Fifteenth Embodimenthorizontally positioned heat sink of the present invention with sectionG-G removed.

FIG. 28 shows an assembled perspective view of an Sixteenth EmbodimentLED lighting device.

FIG. 29 shows a partial view of an Seventeenth Embodiment LED lightingdevice.

FIG. 30 shows a partial magnified view of an Seventeenth Embodiment LEDlighting device.

FIG. 31 shows a partially exploded view of the LED assembly of aSeventeenth Embodiment LED lighting device.

FIG. 32 shows a LED surface mount chip with wide angle light emission.

FIG. 33 shows a LED surface mount chip with narrow angle light emission.

FIG. 34 shows a power LED surface mount chip with narrow angle lightemission.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following embodiments are presented for a thorough teaching of thepresent invention. To aid the reader of this teaching, the variousembodiments with their accompanying figures will be explored seriatim ina stand-alone manner whenever possible.

First Embodiment of the Present Invention

FIG. 1 shows a partially exploded perspective view of a LED lightingdevice 1 consisting of a metal clad printed circuit board 3 with anarray of LEDs 2 mounted thereon. Shown below the said items is anextruded aluminum heat sink 9 with a generally flat surface 4 which ismechanically attached to a housing 6 which is attached to a bayonet base8 containing two locating lugs 7. The bayonet base illustrated is a typeB22d. However, this teaching is not limited to the said bayonet base. Atransparent cover 3 a is also provided which can come as atransparent/translucent plastic cover or it can have multipleperforations if air flow is needed as will be described in subsequentdescriptions of various embodiments of the present invention. Thehousing 6 contains no built in ballast. Note section A-A in said FIG. 1for FIG. 2 description.

FIG. 2 shows an assembled perspective view of a LED lighting device in avertical position. We will now discuss the thermal aspects of the heatsink 9. When the heat sink 9 begins to absorb heat by conduction fromthe LEDs 2 via thermally conductive PCB 3, thermally mounted to heatsink 9, air currents will begin to flow. The hottest parts of the heatsink will be the internal spaces of fins 9 b, 9 c, 9 d and 9 e locatedin the crowded areas of the heat sink 9 fins. For clarity heat sink 9fins 9 b, 9 c, 9 d and 9 e have been cut away at section A-A in FIG. 1to show internal air currents 7 a thru 7 d. Now therefore, air currentswill begin to form, illustrated by arrows 7 a, thru 7 d. The reader isencouraged to imagine these air currents as occurring not just partiallydistal to the heat sink 9 fin bottoms as shown by arrows 7 a thru 7 d,but also very much proximal to the deep inner fin parts of the heat sink9 where little air current motion is going on partly due to a crowdingeffect by the closely spaced heat sink 9 fins. The reason for this isthat there is no high velocity artificially forced air movement such asprovided by a fan, for example. This is a fundamentally inefficient heatsink. Why?

High school physics teaches us that hot air rises up in still air. Sonow let us imagine that air depicted by arrow 7 a is moving up betweenthe heat sink 9 fins. It will absorb heat from said fins. By the time ithas reached the vertical level of arrow 7 b, it will have heatedsomewhat so that that the ΔT between the heat sink 9 fins issignificantly reduced.

Recollect that heat transfer is a function of temperature difference, ΔTbetween the heat sink 9 and the gently rising air current 7 a thru 7 b.Now therefore we have a conundrum; by the time we have the same said aircurrent reaching arrow 7 c, the said air current is even hotter,reducing the ΔT to almost zero.

Therefore the said air current goes for a free ride to a level depictedby arrow 7 d, doing no heat absorbing work and out into the environment.Additionally, housing 6 hinders the entrance of air currents at thelowest level of the heat sink 9 since it is butted hard up against theheat sink 9, further decreasing heat sink 9 efficiency. This has been asimplistic explanation since there are complex air currents involved inmost heat sink operations, too complex to write here. Suffice to say,the above teaching covers the major effects.

FIG. 3 shows an assembled perspective view of a LED lighting device in ahorizontal position. Here we have a situation much more complex toanalyze. Once again, during operation of LED lighting device 1, heatingwill occur. Air proximal to the LEDs 2 and PCB 3 will absorb heat andwill begin to rise, hitting a brick wall so to speak. Said air currents7 will be forced to bend around the lighting device 1 as depicted byarrow 7 e and up into the environment.

Air currents in and around the heat sink 9 fins are very complex toanalyze. Air currents at 7 f and 7 g depict crudely these air currentsrising out of the interstitial spaces of the heat sink 9 fins.Laboratory data has shown that the heat sink 9 does indeed do areasonable job of heat dissipation, almost as good as in the verticalposition. One can speculate that various turbulent short pathmicro-currents are here occurring in and out of the horizontally placedheat sink 9 fins. Also air currents do not travel along the longitudinalpath depicted in FIG. 2, but rise up perpendicularly from the heat sinkfins.

Nevertheless, the present invention is a useful device because it isinexpensive to manufacture and there is minimal pre or post machiningnecessary on extruded aluminum heat sink 9. A half hoop device with twoend clip hooks made of metal or plastic is also shown fitted to grooves11 a to act as a support when placed in a fixture without a plasticcover as shown in FIG. 1. The said half hoop device with two end-cliphooks can also be a full hoop with the clip hooks placed internally at180° apart. These half hoop or full hoop devices become very necessarywhen this first embodiment light fixture is long; for example they arepresently made in 42 inch (1.07 meters) lengths. Furthermore, these saidhoop devices could be used in other similar embodiments. For clarity ofother descriptions, they will not be illustrated in followingembodiments, but are incorporated herein by reference.

FIG. 3A shows an assembled perspective view of a First Embodiment LEDlighting device in a vertical position similar to device illustrated inFIGS. 1 thru 3. Note that a slot 9 b has been added in the area labeledM1.

FIG. 3B shows a magnified view of area M1 of FIG. 3A. An exemplary slot9 b has been added which cuts thru the PCB 3 a and heat sink base 4 a(shown in FIG. 3a ), exposing the attachment bases of heat sink fins 9a. Air can now enter thru the slot 9 b and move over the heat sink bases9 a and on out, cooling the said heat sink fins 9, (shown in FIG. 3a )beginning at the hottest part of the said heat sink which is at thejunction of the heat sink fin 9 a and the base 4 a (shown in FIG. 3a ).This is illustrated clearly in FIG. 3C.

FIG. 3C shows an assembled perspective view of a First Embodiment LEDlighting device in a vertical position similar to device illustrated inFIGS. 1 thru 3. Note that a slot 9 a has been added, as shown in FIG.3B. Air currents 7 can now pass right thru the heatsink assembly at themid-point and bring in fresh cooling air, thus increasing the overallefficiency of the said heatsink assembly. Laboratory experiments haveproven this invention to work. For example, adding only two of suchslots as illustrated in the previous few paragraphs resulted in anoverall reduction of heat sink temperature of approximately 10-15° C.This may seem a little, but it is not; lowering a temperature evenslightly can increase LED life substantially.

Second Embodiment of the Present Invention

FIG. 4 shows a partially exploded perspective view of a SecondEmbodiment LED lighting device 10 consisting of a metal clad printedcircuit board 13 with an array of LEDs 12 mounted transversely thereonas compared to the First Embodiment. Shown below the said items is anextruded aluminum heat sink 19 with a generally flat surface 14 which ismechanically attached to a housing 16 which is attached to a bayonetbase 18 containing two locating lugs 17. The bayonet base illustrated isa type B22d. However, this teaching is not limited to the said bayonetbase. As can be seen in FIG. 4 and subsequent figures, the LEDs 12 arenow situated transversely as compared to the First Embodiment. This isto allow slots 24 to be cut thru printed circuit board 13 for reasonsexplained hereafter. Extruded aluminum heat sink 19 with a generallyflat surface 14 now has been post machined with transverse slots 23 inthe said PCB deep enough to expose the bottoms of the heat sink 19 fins.This embodiment illustrates an extreme example of multiple slots for alarge heat dissipating capability.

FIG. 4A shows a view of a Second Embodiment LED lighting device PCBlayout in a partial sectional format to show traces connecting thevarious LEDs. PCB 13 is shown with slots 24, mounting holes 13 b, andelectrical traces 13 c. PCB dimensions are shown as an example, being 57mm width and 407 mm length. LEDs 12 are shown with their diode symbolsto the immediate right of each LED. To the untrained eye, traces 13 care a little difficult to see, but a PCB designer would immediatelyrecognize them. On the top section are pads labeled IN1 and IN2. AlsoD1, D2, D3, D4 are steering diodes ensuring that the LED array alwaysreceives the correct voltage polarity regardless of the IN1 and IN2power connection polarity. This example is illustrates clearly that amultiply slotted PCB is indeed possible and practical. The 407 mm lengthPCB is only one example shown. LED array panels of this general typehave been made with lengths of up to two or three meters.

FIG. 5 shows an assembled perspective view of a Second Embodiment LEDlighting device 10 consisting of a metal clad printed circuit board 13with an array of LEDs 12 mounted transversely thereon as compared to theFirst Embodiment. Shown below the said items is an extruded aluminumheat sink 19 with a generally flat surface 14 which is mechanicallyattached to a housing 16 which is attached to a bayonet base 18containing two locating lugs 17. The bayonet base illustrated is a typeB22d. However, this teaching is not limited to the said bayonet base.

As can be seen in FIG. 5 and subsequent figures, the LEDs 12 are nowsituated transversely as compared to the First Embodiment. This is toallow slots 24 to be cut thru printed circuit board 13 for reasonsexplained hereafter. Extruded aluminum heat sink 19 with a generallyflat surface 14 which has been post machined with said transverse slotsmatching the said slots 24 in the said PCB deep enough to expose thebottoms of the heat sink 19 fins. Slots 23 from FIG. 4 are now directlybelow the matching slots 24 on the PCB. Notice that the heat dissipatingarea of heat sink 19 has not been disturbed too much and there is stillample flat surface 14 left for conductive heat bonding to the PCB.

FIG. 6 shows a perspective sectional view of a Second Embodiment LEDlighting device heat sink. Sectional views B-B and C-C will now bediscussed.

FIG. 7 shows a second perspective sectional view of a Second EmbodimentLED lighting device heat sink with section B-B details. When in anoperational heated condition, the heat sink 19 will cause air currentsto flow upwards. Unlike the conditions described in the first embodimentwe now have a far more efficient air current flow. One of the basictenets of convective heat transfer is short thermal paths and airvelocity and turbulence. Here we have achieved these to a reasonabledegree. The air current depicted by arrow 27 traverses right thru theslot in the PCB (24 in FIG. 5) and the slot 23 on said heat sink 19 andthen passes past the exposed fins 22 and on out. Additionally, the sharpedges of the slots produce a variety of micro turbulent effects, aidingin heat transfer between the air and the metal heat sink. In theAmerican vernacular, get the air in, grab some heat from the heat sinkand “get out of Dodge” and allow a fresh current of air to come in andrepeat the process. The inventor has dubbed this process “Short PathHeat Transfer”

FIG. 8 shows an end view of a First Embodiment LED lighting device heatsink.

FIG. 9 shows a sectional end view C-C of a Second Embodiment LEDlighting device heat sink. The arrows 7 and 27 speak for themselves. Inthe former case as shown in FIG. 8, no air currents 7 can flow thru heatsink 9. In the latter case shown in FIG. 9, however, air currents 27 doflow fast and free thru heat sink 19 via the slot 23 (shown with a crosshatch for easy identification), cut into the surface 14 of heat sink 19.

Third Embodiment of the Present Invention

FIG. 10 shows an assembled perspective view of a Third Embodiment LEDlighting device 39. It consists of a plurality of individual heat sinkfins 30 with LEDs 34 mounted on the bent portions of heat sink fins 30.The entire assembly is fastened to housing 36, bayonet base 32containing two locating lugs 33. The entire heatsink and LED assembliesare fastened to the housing using appropriate fasteners 37 and spacers38 as shown in FIG. 10.

PCBs, will no longer be shown in further descriptions to not overcrowdthe illustrations and the cost effective manufacturing and wiringtechnique will not be discussed since it is well known in the art.

The heat sink fins 30 with their bent portion are now not extrusions butstamped metal devices. The said stamped metal can be the metal clad PCBmaterial used in previous embodiments or conventional thin sheet metalwith the LEDs 34 mounted electrically insulated from the heat sink fins30, but thermally conductive. A variety of techniques are known in theart. Serial/parallel electrical connections to the LED arrays are alsowell known in the art and need not be discussed herein. For example allthe LEDs 34 could be solder flowed on one appropriately slotted PCB andthen the said PCB LED assembly is solder flowed to all the saidheatsinks fins 30 in one manufacturing operation using various assemblyjigs etc.

FIG. 11 shows a partial assembled perspective view of the said ThirdEmbodiment LED lighting device 39 of FIG. 10. Air currents depicted byarrows 27 can be seen to flow freely cooling each LED 34 heat sink 30segment. This short path fast air flow device has proven to be veryefficient.

Generally each heat sink 30 segment is should be sized to have an areaof 30 to 45 square centimeters per Watt of total led power dissipationon each heatsink fin 30 segment. This is a tall order in many respectsfor a single fin. The next Fourth Embodiment helps us out here bydoubling the fin area. It is important to note that the LEDs must be ata fairly higher temperature than the environment for heat transfer tooccur. So it is a cool-me-if-you-can game between the LED and thethermal engineer. Enough said; it is all in the skill of the art.

Fourth Embodiment of the Present Invention

FIG. 12 shows an assembled perspective view of a Fourth Embodiment LEDlighting device 49. It consists of a plurality of individual heat sinkfins 40 with LEDs 44 mounted on the double bent portions of heat sinkfins 40. The entire assembly is fastened to housing 36, bayonet base 33containing two locating lugs 33, using appropriate fasteners and spacers(not shown). The cost effective manufacturing and wiring technique willnot be discussed since it is well known in the art. The heat sink fins30 with their double bent portion are now not extrusions but stampedmetal devices. The said stamped metal can be the metal clad PCB materialused in previous embodiments or thin sheet metal with the LEDs 44mounted electrically insulated from the double heat sink fins 30, butthermally conductive. A number of techniques are known in the art.

FIG. 13 shows a partial assembled perspective view of the said FourthEmbodiment LED lighting device 41. Air currents depicted by arrows 27can be seen to flow freely cooling each LED 44 heat sink 40 segments.This short path fast air flow device has proven to be very efficient.This fourth embodiment has a higher power dissipation capability thanthe third embodiment due to the double surface area of the heat sink 40.

Fifth Embodiment of the Present Invention

FIG. 14 shows a one section perspective view of a Fifth Embodiment LEDlighting device 61. It is identical to the sections in FIG. 12 with theexception that slots 62 have been added. Now then the neophyte will say“adding slots reduces the heat sink area”. Not so; if the slot width isthe same as the heat sink fin thickness, the area is increased by theadded annular area of the heat sink fin thickness . . . . Herein we setforth the explanation. Let us imagine a heat sink fin that is one tenthof an inch thick. For easy mental calculation, let's cut a rectangularslot one tenth of an inch wide and one inch long. Now from each side ofthe said fin we have removed:

-   -   (0.10×1.0) inches+(First side of rectangular surface)    -   (0.10×1.0) inches+(Second side of rectangular surface)    -   =0.02 square inches

However we have exposed the inner thickness of the said fin thus:

-   -   (0.10×1.0) inches+(First long thickness side of rectangular        opening)    -   (0.10×1.0) inches+(Second long thickness side of rectangular        opening)    -   (0.10×0.10) inches+(First short thickness side of rectangular        opening)    -   (0.10×0.10) inches+(Second short thickness side of rectangular        opening)    -   =0.022 square inches

Now therefore, we have created a heat sink fin 60 which is slightlybetter in area and allows more free airflow as depicted by arrow 27.Additionally, the sharp edges of the slots produce a variety of microturbulent effects increasing convective heat transfer. Moving airturbulence disrupts laminar air flow which in turn achieves betterconvective heat transfer. The slot population density is limited by theheat sink fin 60's thermal conductivity since slotting interferes withthe said fin's conductive heat transfer. So for example, if the fin wascopper, it could have twice the number of slots as aluminum since copperhas roughly two times better heat conduction. Also slot orientation isimportant. Notice that FIG. 14 shows the slots in a radial pattern. Thisnot an accident; this configuration allows fin 60 heat conduction toradiate out radially and thus the slots 62 will be supplied with ampleheat from its source which is the top portion where the LEDs 44 arelocated.

Although the inventor demonstrates that heat sink area can be maintainedwhen slots, holes or other shape of openings are properly applied, theremay be other cases where a relatively small reduction of heat sink areamay be allowed if the cooling advantages outweigh the loss of said heatsink area and are hereby incorporated by reference. As a general note,when dealing with a heatsink base that has fins attached to the saidbase, it is not necessary to maintain the same exposed surface area ofthe said base because the primary function of the base is to conductheat to the fins, not to dissipate the majority of the heat. This is whythe said base is usually much thicker than the fins. However when slots,holes or other shape of openings are placed on the fins, maintaining thesurface area is important. Even so, the said slots, holes or other shapeof openings can be larger if experiment shows that air flow is improvedand heat dissipation is increased. It's all in the art of the thermalscience involved and laboratory experimentation, and therefore thesedescribed techniques are incorporated by reference.

Sixth Embodiment of the Present Invention

FIG. 15 shows a one section perspective view of a Sixth Embodiment LEDlighting device 71 wherein a plurality of holes have been added insteadof slots. With judicious hole 72 sizing and number and placement of saidholes, this heat sink 70 has the greatest potential for efficient shortpath air circulation. Once again arrow 27 illustrates the short path airflow.

Seventh Embodiment of the Present Invention

FIG. 15A shows a one section perspective view of a Seventh EmbodimentLED lighting device 61 a wherein a plurality of openings have been madeusing a metal piercing technique which does not remove any metal such asin drilling or punching holes. Once again, heatsink area is increasedand air flow is improved. The view in FIG. 15A is reversed for clarity.The LEDs 44 are distal, mounted on L bend 61 b, hence the dashed linesindicating their presence. The heatsink fin 60 a is pierced with aplurality of openings 62 a thru which air can circulate. When the heatsink fin 60 a is pierced by a hardened tool spike that generally isshaped like a sharp nail point, an opening 62 a is forced into the metalfin 60 a. Additionally, triangular segments 63 are also produced whichonce again give rise to increased exposed surface area due to thetriangular segments 63 thickness sections. Arrow 27 illustrates air flowthru opening 62 a.

Eighth Embodiment of the Present Invention

FIG. 15B shows a one section perspective view of a Eighth Embodiment LEDlighting device 71 a wherein a plurality of openings have been madeusing a metal stamping technique which does not remove any metal such asin drilling or punching holes. Once again, heatsink area is increasedand air flow is improved. The view in FIG. 15B is reversed for clarity.The LEDs 44 are distal, mounted on L bend 71 b, hence the dashed linesindicating their presence. The heatsink fin 70 a is pierced with aplurality of openings 72 a thru which air can circulate. When the heatsink fin 70 a is stamped with a hardened stamping and partial punchingtool, an opening 72 a is forced into the metal fin 70 a. Additionally,bridge-like segments 73 are also produced which once again give rise toincreased exposed surface area due to the bridge-like segments 73thickness sections. Arrow 27 illustrates air flow thru opening 72 a.

Ninth Embodiment of the Present Invention

FIG. 16 shows a partially exploded perspective view of a NinthEmbodiment LED lighting device 59. Its purpose is to produce a lightingdevice as the previous embodiments, but having an omnidirectional lightemission capability. It consists of heat sink sections 50 with slots 51,and LEDs 56 mounted on bent portions of said heat sinks 50 which arefastened to a central hub 55. The said assembly is attached to a housingrim 57 which is an integral part of housing 58 with a base bayonet 57with two prongs 53. As in previous illustrations, the bayonet baseillustrated is a type B22d. However, this teaching is not limited to thesaid bayonet base. An LED 56 embellished end cap 68 is also shownexploded from the fixture 59 for clarity. When assembled, the top cap 68is edge bonded to the plurality of heat sinks 50 using thermallyconductive epoxy or the like to thermally couple the LEDs 56 on said topcap to the plurality of heat sinks 50. To not impede airflow, aplurality of openings 60 is also shown. Once again, electricalconnections are not shown; they are well known in the art. The baseportion 58, 57 can contain ballast electronics which are also well knownin the art and are not illustrated.

FIG. 17 shows an assembled view of the Ninth Embodiment LED lightingdevice 59. The slots 51 are carefully designed so as to keep the heatsink area the same as discussed previously. This Ninth Embodiment LEDlighting device 59 is capable of very efficient heat dissipation. Asmentioned previously, when assembled, the top cap 68 is edge bonded tothe plurality of heat sinks 50 using thermally conductive epoxy or thelike to thermally couple the LEDs 56 on said top cap 68 to the pluralityof heat sinks 50. A transparent perforated plastic cover is generallyused with this lighting device 69. (Not shown here, but is illustratedin FIG. 18A).

Tenth Embodiment of the Present Invention

FIG. 18 shows an assembled view of the Tenth Embodiment LED lightingdevice 69, wherein the plurality of heat sinks 70 are made frompreferably, but not limited to, perforated aluminum. The holes 61 arecarefully designed so as to keep the heat sink area substantially thesame surface area as discussed previously. This Tenth Embodiment LEDlighting device 69 is capable of very efficient heat dissipation, evenbetter than Embodiment Nine. The top cap 68 is edge bonded to theplurality of heat sinks 70 using thermally conductive epoxy or the liketo thermally couple the LEDs 56 on said top cap to the plurality of heatsinks 70. A transparent perforated plastic cover is generally used withthis lighting device 69. (Shown in FIG. 18A). The said plastic cover isalso carefully designed, with little or no perforations in front of theLEDs, and large perforations between the heat sink 70 “wings”. The topportion of the lighting device 68 is also covered by the same said coverand slotted in the triangular region 71 between the “star” patternedLEDs 56. The better this said lighting device can “breathe”, the coolerit will run.

FIG. 18A shows an assembled view of the Eighth Embodiment LED lightingdevice 69, wherein none of the interior is shown. Only the transparentor translucent protective plastic cover 71 and base portion isillustrated. The said assembly is attached to a housing rim 57 which isan integral part of housing 58 with a base bayonet 57 with two prongs53. The cover portion 71 contains a plurality of slots 72 designed toallow air to pass into and out of the LED light fixture. On the topportion are shown triangular openings 73 to allow air in or out asdescribed for the said slots. Although slots and triangular openings areshown, this invention is not limited to this said configuration. Duringmanufacturing, other constraints may apply, necessitating other types ofopenings and are hereby incorporated by reference. Additionally, theportions of the said plastic cover 71 can also have lenses molded in theareas directly in front of each LED for further light dispersion and ishereby incorporated by reference.

Other Applications of the Present Invention

Heretofore the novel heat sink structure has been taught as applied toLED lighting devices. Nevertheless, in order to comply with therequirement to offer a full disclosure of the present invention, theinventor will now illustrate an alternate semiconductor coolingapplication.

FIG. 19 illustrates a perspective view of a horizontally positioned verycommon heat sink 80 as used by millions of electronic devices. Itconsists of a flat surface portion 88 with a plurality of fins 89. It ispredominantly made by an aluminum extrusion process or a castingprocess. Mounted on the surface portion 88 are several power dissipatingsemiconductor devices 87. Under operation these devices 87 generateheat; which heat is conductively transferred to the heat sink 80containing a plurality of fins 89. Air currents begin to flow asdescribed in the description of FIG. 3. As shown by arrow 86, rising aircurrents cannot traverse thru the bottom surface 88 of heat sink 80 anddiverge around the said heat sink 80. Complex micro air currents in andaround the heat sink 80 fins 89 do a reasonable job of heat transfer tothe ambient air.

Now therefore, the well understood science of heat transfer teaches usthat still air has an extremely low thermal conductivity of about 0.026W/mK, depending upon altitude, barometric pressure, humidity etc.However moving air has a much better heat transfer capability.Subsequently deep in the central inner parts of the heat sink 80 littleair current movement is going on, hence the inefficiency of the heatsink 80.

Now let us discuss forced air cooling of the heat sink 80. According toLangmuir's laminar flow theory, smooth and even air flow over a surfacedoes not result in efficient heat transfer due to a “boundary layereffect” wherein the air atomically close to the surface over which theair is flowing does not move. Thus heat transfer is radiative in naturefrom the surface to the moving air close above the said surface. How dowe overcome this? If we cause the air movement to be turbulent, heattransfer is more efficient since the turbulence disrupts the boundarylayer effect to a significantly large degree by a scrubbing action ofirregular atmospheric motion especially when characterized byup-and-down micro current turbulence.

Air turbulence is greatly induced when air is pushed, and is less whenair is sucked thru a heat sink's fins. As explained to this inventor bya seasoned aeronautical engineer several years ago, air molecules are tobe likened to light ping pong balls that refuse to be pushed in thedirection of the forced air, but can be easily sucked up by a vacuumcleaner. Pushing air causes turbulence, while sucking air tends towardssmoother air flow.

Now if we introduce holes or slots in the heat sinks fins, furthersubtle effects occur. For example, moving air over a hole or slot willpull additional air thru these said slots or holes due to the “Bernoullieffect”, further causing more air flow and turbulence due to “edgeeffects” thus creating better heat transfer. One type of “edge effect”occurs when moving air over an even surface suddenly passes over a sharpdiscontinuity on the said surface such as an edge or trough or channeletc. The moving air experiences a disruption and turbulence results,further disrupting laminar flow and convective heat transfer isaugmented.

The above has been a greatly simplified explanation since a rigoroustreatment of the subject would is beyond the scope if this teaching.

Eleventh Embodiment of the Present Invention

FIG. 20 illustrates a perspective view of an Eleventh Embodiment of thepresent invention. It consists of a horizontally positioned heat sink90, a flat surface portion 98 with a plurality of fins 99. Mounted onthe surface portion 98 are several power dissipating semiconductordevices 87. Under operation these devices 87 generate heat; which heatis conductively transferred to the heat sink 90 containing a pluralityof fins 99. Air currents begin to flow; but this time thru the heat sink90 via slots 95 as shown by arrow 96, past the exposed bottoms of theheat sink 90 fins 94. Now we have a faster air movement and cool airentering at the base of the said fins 94. This is a more efficient heatsink than the one in FIG. 19. Section D-D is removed and the remainderdepicted in FIG. 21.

FIG. 21 illustrates a partial perspective sectional view of ahorizontally positioned heat sink 90 as used in the present inventionwhere the proximal section D-D depicted in FIG. 20 has been removed. Itconsists of a flat surface portion 98 with a plurality of fins 99.Mounted on the surface portion 98 are several power dissipatingsemiconductor devices 87. Under operation these devices 87 generateheat; which heat is conductively transferred to the heat sink 90containing a plurality of fins 99. Air currents begin to flow; but thistime thru the heat sink 90 via slots 95 as shown by arrows 96, past theexposed bottoms of the heat sink 90 fins 94. Now we have a faster airmovement and cool air entering at the base of the said fins 94. Thesectional view C-C shows the exposed fins 94 clearly. The depth of theslots 95 is just deep enough to expose the bottoms on the Fins 90. Thisis a more efficient heat sink than the one depicted in FIG. 19. Also, asnoted earlier in these teachings, slots were shown on the heat sink 90.Holes or other shape of openings may be used depending on the engineer'sdesign constraints and are hereby incorporated by reference.

As a note, the heat sinks 90 as depicted in FIGS. 20 and 21 do not haveto be in a horizontal position; they are more efficient than heat sink80 in other orientations. In the vernacular, we have allowed the heatsink 90 to “breathe” better.

Twelfth Embodiment of the Present Invention

FIG. 22 illustrates a Twelfth Embodiment of the present invention. It isa perspective view of a horizontally positioned heat sink 100 as used inthe present invention. It consists of a flat surface portion 108 with aplurality of fins 104 and a plurality of holes 105 drilled deep enoughto expose the bottoms of fins 104. Mounted on the surface portion 108are several power dissipating semiconductor devices 87. Under operationthese devices 87 generate heat; which heat is conductively transferredto the heat sink 100 containing a plurality of fins 104 with holes 105.Air currents begin to flow; but this time thru the heat sink 100 viaholes 105, past the exposed bottoms of the heat sink 100 fins 104. Nowwe have a faster air movement and cool air entering at the base of thesaid fins 104. This is a more efficient heat sink than the one in FIG.19. FIG. 22 also shows additional side holes 205 being added to fins 104for more efficiency. The side holes, which are drilled just above thebase portion 106, can be drilled thru all the fins 104 or only aselected few as desired. Once again it is recommended that the heatsink's surface maintains the same area or more if possible.

Thirteenth Embodiment of the Present Invention

FIG. 23 illustrates a Thirteenth Embodiment of the present invention. Itis a perspective view of a horizontally positioned heat sink 300 withfins 304 as used in the present invention. This is a variant of the heatsink of FIG. 23 with LED devices 387 mounted on flat surface 308. Thisis a useful device for non-room lighting such as embedded lighting forindustrial applications and machine interior inspection or machineoperating etc.

Fourteenth Embodiment of the Present Invention

FIG. 24 illustrates a Fourteenth Embodiment of the present invention. Itis a perspective view of a horizontally positioned double sided heatsink 400 with fins 404 positioned on each side of base 406. A flat baseportion 407 is used to mount either power LEDs or power semiconductors(not shown) as used in the present invention. This is a heat sink forspecialty applications. In cases where side drilling is not desired andpartial drilling of one sided finned heatsinks is also not wanted, analternate is now offered. Thru-drilling in the interstitial gaps betweenthe heat sink fins can be done to achieve good results. The next figurewill show section E-E removed.

FIG. 25 illustrates view E-E of FIG. 26 showing holes 410 aligned withinterstitial gaps between the heat sink fins 404. As shown by arrow 410(and dashed line at point of arrow 410 showing hole alignment), FIG. 25Ais a magnified view F-F of FIG. 25 showing the holes 412 thru base 406.Note dashed line 413 indicating alignment of holes 412 with the saidinterstitial spaces between the said heatsink fins 404.

Fifteenth Embodiment of the Present Invention

FIG. 26 illustrates a Fifteenth Embodiment of the present invention. Itis a perspective view of a horizontally positioned double sided heatsink 500 with fins 504 positioned on each side of base portion 506. Aflat portion 507 both top and bottom is used to mount either power LEDsor power semiconductors (not shown) as used in the present invention.This is a heat sink for higher power dissipation capability. Holes 505are shown. These said holes are drilled large enough to expose the basesof fins 504, and deep enough to expose the fins save the last fins 504 aand 504 b for cosmetic purposes and not to interfere with the flatportions 507. The next figure will show section G-G removed.

FIG. 27 illustrates the heat sink of FIG. 26 with section G-G removed.Note the exposed fins 510 caused by the drilled holes as described inFIG. 26. During operation, this heatsink now has air moving in a shortpath straight thru the double fins 504 since the base 506 portions havebeen drilled out. Air flow as represented by arrow 596 shows thisclearly. Once again it is recommended that the heat sink's surfacemaintains the same area or more if possible.

Sixteenth Embodiment of the Present Invention

FIG. 28 illustrates side view of a Sixteenth Embodiment LED lightfixture 600 of the present invention. This is a high power luminaire aswould be used in tall warehouses, lamp posts, stadiums, schoolgymnasiums, etc. These exclusively use high power LEDs and generallycome in 200 watt to 500 watt units and up units.

The illustration in FIG. 28 shows a generally circular luminaire but isnot limited to this style. A perimetrical structure such as is used insome modern street lights and commercial wall lights etc. is alsopossible.

Cooling is a massive task; as is water proofing and internal preventionof moisture build up. The said luminaire consists of a large one pieceheatsink 640 with fins 641 and a flat base 650. Mounted on the bottom ofbase 650 is a highly heat conductive (such as copper) heat spreader 662of special design. A plurality of high power LEDs 660 is mounted on saidheat spreader 662. A transparent/translucent cover 670 is provided andan optional large reflector 680 is shown.

Although the said fins 641 are shown to be on the top only, some extrafins could also be placed on selected areas on the bottom (not shown)side also and are hereby incorporated by reference.

To give the reader an idea of size, the heat sink 650 can be as large asa foot (305 mm) or more in diameter. Sitting above heat sink 640 is acentral hub section containing a power supply and other optional devicessuch as, for example ambient light sensors, wired or wirelesscommunication devices etc., with attached “eye Bolt” 610 for mountingpurposes. Side bolts 622 are also provided for alternate mountingmethods as well.

FIG. 29 illustrates a front face view of heat sink 640 with LEDassembly. Slots 630 are milled thru base 650 shown in FIG. 28 exposingthe bottom parts of heatsink 640 fins 642. Note circular section H-H.

FIG. 30 illustrates a magnified view section H-H of FIG. 29. Slots 630are visible and exposed fin sections 642 are clearly shown. Why is thisheatsink efficient? The thick base 650 (FIG. 28) conducts the intenseheat flux radially outward very fast and the fins 641 sections dissipatethe said heat efficiently due to the cooling air moving thru the slotsand directly around the fins and subsequently up into the ambientenvironment. The cooling air first strikes the hottest part of theheatsink fins and then follows a short path up and out, dragging newcooling air up with it. If even higher power LED lighting is desired,the base portion 650 can be made of copper which has twice the thermalconductivity of aluminum, while the fins are still aluminum. The idea isto conduct the heat out of the middle portion where the LEDs are locatedas quickly as possible. Additionally, graphene layer/s could be addedwithin the base portion 650 for even faster heat conduction and ishereby incorporated by reference.

Seventeenth Embodiment of the Present Invention

FIG. 31 illustrates a Seventeenth Embodiment of the present invention.It is a front face view only of an alternate heat sink and LED assemblyfor the luminaire shown in FIG. 28. The heatsink of this embodiment is asix part unit, pie shaped in this illustration, but not limited to saidshape, and assembled together as shown. One segment is shown jutting outfor clarity of description. This method of constructing the luminaireheat sink/LED assembly is advantageous for two reasons. First we areworking with a smaller assembly and second, field replacement ofsections of the LED/heatsink assemblies is easier than working on thewhole massive unit. Indeed making each section pluggable would makefield repair easy. Additionally, each said section could have its ownsmaller power supply which is cheap and adds further redundancy to powersupply reliability. If one fails, the other five segments would stillprovide light. There are a variety ways to practice this invention andare hereby incorporated by reference.

Led Lighting Devices—Short Description

LED lighting is fast becoming as ubiquitous as the incandescent bulb wasin the last century. Worldwide, manufacturers and lighting contractorsare trampling over each other to get a piece of the action in thisbusiness. Generally, LEDs for lighting purposes come in three classesand two types within those classes.

-   -   Class 1—Low power LEDs—less than 1 Watt dissipation.    -   Class 2—High power LEDs—greater than 1 Watt dissipation.    -   Class 3—Very High power multi-chip LED assemblies—greater than        10 Watts dissipation and supremely difficult to cool.

The two types in class 1 and class 2 are:

-   -   1. Wide angle luminance, about 100-165 degrees in a scattered        fashion due to a flat LED emitting face.    -   2. Narrow angle luminance, about 20-60 degrees typically in a        Lambertian distribution due to a molded-in lens.

Class 3 devices can be narrow angle up to about 5 watts while higherpower units use a plurality of individual chips mounted as an array inone package with a common phosphor applied over the entire said LED chiparray and so a narrow angle is more difficult. Indeed, multi-chip unitsare being made with up to 100 watts dissipation and more. They aresupremely difficult to cool with ambient air since the small area heatflux from the multi-chip modules is extremely high. Even solid copperheat transfer is tenuous at best. Forced air cooling is greeted withcontempt by customers due to the noise, low reliability and dustaccumulation of fans. Dust is impinged upon heat sink fins due to theorders of magnitude greater air flow passing over the said heat sinkfins as compared to normal non-forced air flow.

LEDs used in the present invention are mostly of the low power typebecause they are individually inexpensive and are thermally manageable.A typical fixture of the present invention can use dozens of low powerLED devices, each with less than one watt dissipation. However, thepresent invention does accommodate high power LED technology since themarket demands it.

FIG. 32 illustrates a sectional view of a low power surface mount LED100 with wide angle characteristics. It consists of a housing 110, acopper lead frame 111, upon which is bonded a light emitting siliconchip 112. A wire bond 115 connects the top section of chip 112 to theother lead 111 (left copper lead in FIG. 22). A rather large phosphorfill 114 is provided which emits white light. The copper leads 111provide conductive heat transfer to a printed circuit board (not shown)on which the LED 100 is soldered.

FIG. 33 illustrates a sectional view of a low power surface mount LED120 with narrow angle characteristics. It consists of a housing 115, acopper lead frame 131, upon which is bonded a light emitting siliconchip 132. A wire bond 134 connects the top section of chip 132 to theother lead 131 (left copper lead in FIG. 33). Unlike in the wide angleLED shown in FIG. 32, a relatively compact phosphor covering 124surrounds the chip which emits white light in an intense almost pointsource configuration. A molded focusing lens 119 is also provided. Thelens 119 in combination with the mentioned small phosphor 124 the lightemission angle considerably. The copper leads 131 provide conductiveheat transfer to a printed circuit board (not shown) on which the LED110 is soldered.

FIG. 34 illustrates a sectional view of a power surface mount LED 130with narrow angle characteristics. It consists of a housing 135, acopper lead frame 141, upon which is bonded a light emitting siliconchip 142. A wire bond 146 connects the top section of chip 142 to theother lead 141 (left copper lead in FIG. 34). Unlike in the wide angleLED shown in FIG. 32, a relatively compact phosphor covering 134surrounds the chip which emits white light in an intense almost pointsource configuration. A molded focusing lens 129 is also provided. Thelens 129 in combination with the mentioned small phosphor 144 narrowsthe light emission angle considerably. The copper leads 141 provideconductive heat transfer to a printed circuit board (not shown) on whichthe LED 130 is soldered. Additionally, a copper or other highlyconductive material slug 145 removes heat from the silicon chip directlyto the exposed bottom portion of LED 130 which can be soldered to a PCBas well as the leads 141.

High power LEDs use a great variety of mounting methods from large areasolder flow to directly bolting to a big heatsink.

Summary Ramifications and Scope

The fixtures described in this teaching provide the installationprofessional several advantages, some of which are summarized asfollows:

1. Low cost.

2. Universal mounting positions.

3. Minimum installation labor.

4. Retrofit versatility.

5. Light weight.

6. Low power consumption.

A hidden feature of LED light fixtures is that these fixtures can bemade to produce white, red, green, blue or yellow light. For example ayellow or red light fixture may be used in a chemistry lab or photoprocessing lab where white light is not desired. Indeed the same fixturecould be made to have two or more color LEDs so that one fixture canperform both jobs as necessary. This was not easily done withfluorescent light fixtures of the past. Furthermore RGB LED lights canproduce a variety of colors necessary by controlling the power to eachof the three led devices. Generally this is done using Pulse WidthModulation techniques which will not be described here since it is wellunderstood in the art. These features can be controlled remotely byPower Line Signal or Optical Signal or Radio Frequency Signal means.They will not be described since they also are well known in the art.These control devices are available on the commercial market as completemodules. Most are covered by their own patent portfolios; thus thisdisclosure does not claim their technology, but does claim the use ofthese said control devices in the specific environment of LED devicesdescribed herein.

RGB LEDs can also be used for white light variations such a “warm white”for winter and a “cool white” for summer etc. (“Warm white” is a lowercolor temperature tending towards the yellow whereas a “cool white” is ahigher color temperature tending towards the blue.) None of thedescribed embodiments showed built-in ballasts/power supplies. Althoughthey were not described, the present invention does not preclude theiruse as a built in device but has omitted them for clarity of theteaching

This inventor claims these aspects of the novelty and the claims sectionof this patent reflect this clearly. Although the descriptions abovecontain a number specificities these should not be construed as limitingthe scope of the invention but as merely providing illustrations of someof the presently preferred embodiments of this invention. Thus the scopeof the invention should be determined by the appended claims and theirlegal equivalents rather than by the examples provided.

The claims are not limited to the various aspects of this disclosure,but are to be afforded the full scope consistent with the language ofthe claims. Structures and functional equivalents of the elements of thevarious aspects described throughout this disclosure that are known orare later come to be known to those skilled in the art are expresslyincorporated herein by reference and are intended to be encompassed bymetes and bounds of the claims. Additionally, nothing disclosed hereinis intended to be dedicated to the public regardless of whether suchdisclosure is explicitly recited in the claims. No claim element is tobe construed under the provisions of 35 U.S.C. § 112, sixth paragraph,unless the element is expressly recited using the phrase “means for” orin the case of a method claim, the element is recited using the phrase“step for”.

What is claimed is:
 1. A lamp assembly, comprising: a plurality of heat sink sections comprising one or more openings for airflow to cool the assembly; wherein the heat sink sections are coupled to a central hub; at least one light emitting diode mounted on a bent portion of a heat sink section; an endcap comprising one or more light emitting diodes, wherein the endcap comprises one or more openings for airflow to cool the assembly; and a cover comprising a plurality of openings for airflow to cool the assembly.
 2. The lamp assembly of claim 1, further comprising: wherein the endcap is edge bonded to the plurality of heat sink sections for coupling the one or more light emitting diodes to the endcap.
 3. The lamp assembly of claim 1, further comprising: wherein the one or more endcap openings are configured in a triangle shape.
 4. The lamp assembly of claim 1, further comprising: wherein the plurality of heat sink sections comprises perforated aluminum.
 5. The lamp assembly of claim 1, further comprising: wherein an endcap opening is disposed between a star configuration of a plurality of light emitting diodes.
 6. The lamp assembly of claim 1, further comprising: wherein the plurality of cover openings encompasses the plurality of heat sink sections and the endcap.
 7. A lamp assembly, comprising: a plurality of heat sink sections comprising one or more openings for airflow to cool the assembly, wherein the heat sink sections are fastened to a central hub; at least one light emitting diode mounted on a bent portion of a heat sink section; an endcap comprising one or more light emitting diodes, wherein the endcap comprises one or more triangle shape openings for airflow to cool the assembly; a cover comprising a plurality of openings for airflow to cool the assembly, and wherein the lamp assembly is configured into a cylindrical shape.
 8. The lamp assembly of claim 7, further comprising: wherein the cover is transparent or translucent.
 9. The lamp assembly of claim 8, further comprising: wherein a cover opening is disposed between a pair of heat sink sections.
 10. The lamp assembly of claim 7, further comprising: wherein a width of a heat sink section opening equals to a thickness of the heat sink section for increasing surface area.
 11. The lamp assembly of claim 7, further comprising: wherein a heat sink section opening is configured in a slot.
 12. The lamp assembly of claim 7, further comprising: wherein a cover opening is configured in a slot.
 13. The lamp assembly of claim 7, further comprising: wherein the one or more light emitting diodes of the endcap is configured in a straight line.
 14. A lamp assembly, comprising: a plurality of heat sink sections comprising one or more slots for airflow to cool the assembly, wherein the heat sink sections are coupled to a central hub; at least one light emitting diode mounted on a bent portion of a heat sink section; an endcap comprising one or more light emitting diodes, wherein the endcap comprises one or more openings for airflow to cool the assembly; a base portion comprising a housing rim and a base bayonet; and a cover comprising a plurality of slots for airflow to cool the assembly.
 15. The lamp assembly of claim 14, further comprising: wherein a plurality of triangle shape endcap openings comprises corners surrounding a central axis.
 16. The lamp assembly of claim 15, further comprising: wherein the plurality of triangle shape endcap openings comprise curved sides disposed at a perimeter of a star configuration of a plurality of light emitting diodes.
 17. The lamp assembly of claim 14, further comprising: wherein the plurality of cover slots is not disposed in front of the at least one light emitting diode.
 18. The lamp assembly of claim 14, further comprising: one or more lenses disposed on the cover and directly in front each of the at least one light emitting diode for light dispersion.
 19. The lamp assembly of claim 14, further comprising: wherein the plurality of heat sink sections are configured in a cylindrical shape.
 20. The lamp assembly of claim 14, further comprising: wherein the at least one light emitting diode mounted on the bent portion of the heat sink section is configured in a straight line. 